Earnings per diluted share of $2.20, an increase of 108% from the
first quarter of 2017

Record quarterly income from operations of $401 million

Record quarterly EBITDA of $579 million

HOUSTON--(BUSINESS WIRE)--May 3, 2018--
Westlake Chemical Corporation (NYSE: WLK) (the "Company" or "Westlake")
today reported net income attributable to the Company of $287 million,
or $2.20 per diluted share, on net sales of $2,150 million. This
represents an increase of $149 million, or $1.14 per diluted share,
compared to the first quarter of 2017 net income of $138 million, or
$1.06 per diluted share, on net sales of $1,943 million. Net income for
the first quarter of 2018 increased versus the prior-year period
primarily due to (1) higher sales prices for major products, resulting
in improved margins; (2) a lower income tax provision resulting from the
reduced U.S. corporate income tax rate under the U.S. Tax Cuts and Jobs
Act (the "Tax Act"); (3) higher sales volumes for caustic soda and PVC
resin; and (4) a $6 million pre-tax gain from the redemption of debt in
February 2018. Net sales for the first quarter of 2018 increased by $207
million compared to net sales for the first quarter of 2017, mainly due
to higher sales prices for our major products and increases in sales
volumes for caustic soda and PVC resin, partially offset by lower
polyethylene sales volume. Income from operations was a record $401
million for the first quarter of 2018 as compared to $234 million for
the first quarter of 2017. The increase in income from operations was
mainly a result of higher margins for our major products and higher
sales volumes for caustic soda and PVC resin, partially offset by lower
polyethylene sales volume. The first quarter of 2017 was negatively
impacted by the turnaround and expansion of the ethylene unit in Calvert
City, Kentucky, as well as other planned turnarounds and unplanned
outages. Transaction and integration-related costs in the first quarter
of 2018 were $7 million, or $0.04 per diluted share.

First quarter 2018 net income attributable to the Company of $287
million, or $2.20 per diluted share, decreased $515 million from the
$802 million, or $6.15 per diluted share, reported in the fourth quarter
of 2017. The fourth quarter of 2017 included a one-time, non-cash tax
benefit of $591 million, or $4.53 per diluted share, associated with the
Tax Act enacted in the fourth quarter of 2017. Excluding the benefits
associated with the Tax Act, net income attributable to the Company for
the first quarter of 2018 increased $76 million, or $0.58 per diluted
share, compared to the fourth quarter of 2017. First quarter 2018 net
income attributable to the Company benefited from higher sales volumes
and margins in the Vinyls segment and a lower effective tax rate. Net
sales for the first quarter of 2018 of $2,150 million were $140 million
higher than fourth quarter 2017 sales of $2,010 million. The increase in
net sales compared to the fourth quarter of 2017 was primarily due to
higher sales volumes and higher prices of our major products in the
Vinyls segment, partially offset by lower polyethylene sales volumes.
Record income from operations for the first quarter of 2018 of $401
million increased $38 million from fourth quarter 2017 income from
operations of $363 million. The increase in income from operations was
primarily due to increased sales volumes and margins in the Vinyls
segment.

"We are very pleased with the record results for the first quarter of
2018 and the continued performance of our businesses. Demand remains
strong for our products in both the Olefins and Vinyls segments due to
continued growth in the Americas, Europe and Asia, and we continue to
benefit from the investments made in 2017 to improve our operations and
reliability," said Albert Chao, President and Chief Executive Officer.
"We are working diligently on the recently announced expansions in our
Vinyls segment and remain focused on capturing the targeted synergies
and cost reductions as well as other opportunities that will improve our
operations across the company."

Net cash provided by operating activities was $225 million and capital
expenditures were $154 million for the first quarter of 2018. As of
March 31, 2018, cash and cash equivalents were $851 million and total
debt was $3,127 million. In February 2018, we redeemed $688 million
(aggregate principal amount) of outstanding 4.625% senior notes due
2021. In March 2018, we delivered irrevocable notices to redeem $450
million (aggregate principal amount) of outstanding 4.875% senior notes
due 2023, with a redemption date of May 15, 2018.

Record EBITDA (earnings before interest expense, income taxes,
depreciation and amortization) of $579 million for the first quarter of
2018 increased $188 million compared to first quarter of 2017 EBITDA of
$391 million. EBITDA for the first quarter of 2018 increased $62 million
compared to fourth quarter of 2017 EBITDA of $517 million. A
reconciliation of EBITDA to reported net income and to net cash provided
by operating activities can be found in the financial schedules at the
end of this press release.

OLEFINS SEGMENT

The Olefins segment income from operations of $163 million for the first
quarter of 2018 decreased $17 million from first quarter 2017 income
from operations of $180 million. This decrease was mainly attributable
to lower polyethylene sales volumes and higher feedstock costs. These
decreases were partially offset by higher sales prices for polyethylene.

Olefins income from operations of $163 million for the first quarter of
2018 decreased $3 million compared to the fourth quarter 2017 income
from operations of $166 million. The decrease in Olefins income from
operations was due to lower polyethylene sales volumes, partially offset
by higher sales volumes and prices for styrene as compared to the prior
quarter.

VINYLS SEGMENT

The Vinyls segment reported record income from operations for the first
quarter of 2018 of $266 million, an increase of $196 million from the
first quarter 2017 income from operations of $70 million. This increase
was mainly attributable to higher sales prices for major products and
higher sales volumes for caustic soda and PVC resin. The first quarter
of 2017 was negatively impacted by the turnaround and expansion of our
ethylene unit in Calvert City, Kentucky, as well as other planned
turnarounds and unplanned outages.

Vinyls income from operations for the first quarter of 2018 of $266
million was $52 million higher than fourth quarter 2017 income from
operations of $214 million. The increase in Vinyls income from
operations resulted from higher sales volumes for all of our major
products, higher caustic soda prices, lower feedstock costs and lower
costs associated with planned turnarounds and unplanned outages.

The statements in this release and the related teleconference
relating to matters that are not historical facts, including statements
regarding targeted synergies and cost reductions, are forward-looking
statements. These forward-looking statements are subject to significant
risks and uncertainties. Actual results could differ materially, based
on factors including, but not limited to: general economic and business
conditions; the cyclical nature of the chemical industry; availability,
cost and volatility of raw materials and utilities, including natural
gas and natural gas liquids from shale production; the price of crude
oil; uncertainties associated with the United States and worldwide
economies, including those due to global economic and financial
conditions; governmental regulatory actions, including environmental
regulation; political unrest; industry production capacity and operating
rates; the supply/demand balance for Westlake's products; competitive
products and pricing pressures; access to capital markets; technological
developments; the effect and results of litigation and settlements of
litigation; operating interruptions; and other risk factors. For more
detailed information about the factors that could cause actual results
to differ materially, please refer to Westlake's Annual Report on Form
10-K for the year ended December 31, 2017, which was filed with the SEC
in February 2018.

Use of Non-GAAP Financial Measures

This release makes reference to certain "non-GAAP" financial
measures, such as EBITDA and net income excluding certain tax benefits,
as defined in Regulation G of the U.S. Securities Exchange Act of 1934,
as amended. We report our financial results in accordance with U.S.
generally accepted accounting principles ("U.S. GAAP"), but believe that
certain non-GAAP financial measures, such as EBITDA, provide useful
supplemental information to investors regarding the underlying business
trends and performance of the company's ongoing operations and are
useful for period-over-period comparisons of such operations. We also
believe providing the non-GAAP measure net income excluding certain tax
benefits will help investors compare results between periods given the
one-time nature of the tax benefit associated with the Tax Act. These
non-GAAP financial measures should be considered as a supplement to, and
not as a substitute for, or superior to, the financial measures prepared
in accordance with U.S. GAAP. A reconciliation of EBITDA to reported net
income and to net cash provided by operating activities can be found in
the financial schedules at the end of this press release.

Westlake Chemical Corporation

Westlake Chemical Corporation is an international manufacturer and
supplier of petrochemicals, polymers and building products with
headquarters in Houston. The company's range of products includes:
ethylene, polyethylene, styrene, propylene, chlor-alkali and derivative
products, PVC suspension and specialty resins, PVC compounds, and PVC
building products including siding, pipe, fittings and specialty
components, windows, fence, deck and film. For more information, visit
the company's web site at www.westlake.com.

Westlake Chemical Corporation Conference Call Information:

A conference call to discuss Westlake Chemical Corporation's first
quarter 2018 results will be held Thursday, May 3, 2018 at 11:00 AM
Eastern Time (10:00 AM Central Time). To access the conference call,
dial (855) 760-8160 or (704) 288-0624 for international callers,
approximately 10 minutes prior to the scheduled start time and reference
passcode 7684638.

A replay of the conference call will be available beginning two hours
after its conclusion until 11:59 p.m. Eastern Time on May 10, 2018. To
hear a replay, dial (855) 859-2056 or (404) 537-3406 for international
callers. The replay passcode is 7684638.

Industry pricing data was obtained from IHS Markit ("IHS"). We have
not independently verified the data.

(2)

Represents average North American spot prices of ethylene over the
period as reported by IHS.

(3)

Represents average North American net transaction prices of
polyethylene low density GP-Film grade over the period as reported
by IHS.

(4)

Represents average North American contract prices of styrene over
the period as reported by IHS.

(5)

Represents average North American United States Gulf Coast
undiscounted contract prices of caustic soda over the period as
reported by IHS. During the first quarter of 2018, IHS discontinued
the previous caustic soda index that we used. For comparability, the
average caustic soda for the prior periods presented are based on
the current index.

(6)

Represents average North American contract prices of chlorine (into
chemicals) over the period as reported by IHS.

(7)

Represents average North American contract prices of polyvinyl
chloride (PVC) over the period as reported by IHS.